Epidemiology of Drinking and Disorders in Border vs. Non-Border Contexts People of Mexican origin constitute the largest subgroup of Hispanics in the US (70 percent), representing 29 percent of the country's immigrant population, a large proportion of which comes to the US from border areas in Mexico. The border, home to the largest concentration of those of Mexican-origin living in the US, has received a great deal of media attention due to high rates of violence, homicide and drug trafficking, but little epidemiologic data exist on substance use or related disorders along the US-Mexico border on either side, or the effect of such stressors. This suggests the need for an in-depth study of alcohol use and related problems within the border context, including an examination of the influence of border proximity and cross-border mobility on alcohol use outcomes. The proposed research aims to describe and explain alcohol use patterns and related problems among Mexican-origin adults living in three pairs of sister metropolitan areas at the Texas-Mexico border, plus, as a contrast, in one adjacent non-border metropolitan area on each side of the border as follows: 1) describe alcohol and drug use patterns and alcohol use disorders in border vs. non-border context on both sides of the border; 2) test a conceptual model explaining the effects of border variables on alcohol and drug use outcomes; 3) describe cross-border mobility on both sides and determine the influence of cross-border mobility on alcohol and drug use patterns and alcohol use disorders. Survey data, from face-to-face household interviews, will be collected on 2,400 Mexican-origin adults over the age of 18 living in three border metropolitan areas (Laredo, McAllen and Brownsville), and one non-border metropolitan area (San Antonio) in Texas, and on 2,400 adults living in three sister metropolitan border counterparts (Nuevo Laredo, Reynosa and Matamoros), and one non-border metropolitan area in Mexico. Hazardous drinking, alcohol use disorders, and drug use will be compared between respondents in border and non-border metropolitan areas on both sides, and between those in Texas and their counterparts in Mexican sister metropolitan areas. Path analysis will be used to test the conceptual model. These findings are expected to increase our understanding of alcohol use patterns and problems in the border context, including the influence of cross-border mobility, and provide valuable data for formulating hypotheses which can be explored in a broader border context. Findings from this application will inform intervention and prevention related to substance use at the border.